ABC | Volume 114, Nº2, February 2020

Update Update of the Brazilian Guideline on Nuclear Cardiology – 2020 Arq Bras Cardiol. 2020; 114(2):325-429 Table 19 – Segmentary analysis of left ventricle motility and systolic thickness by single photon emission computed tomography synchronized with ECG (Gated-SPECT) Score (points) Motility Thickness 0 Normal Normal 1 Mild hypokinesis Mild reduction 2 Moderate hypokinesis Moderate/severe reduction 3 Severe hypokinesis Absence of thickness 4 Akinesis – 5 Dyskinesis – distribution or normal uptake of the radiopharmaceutical in the myocardium; transient low uptake suggestive of ischemia; fixed low uptake suggestive of fibrosis; partially reversible low uptake suggestive of ischemia associated with fibrosis ), should take the presence of the following types of artifacts into account: • Technical artifacts, resulting from inadequate image processing. • Motion artifacts. • Attenuation artifacts, due to interposition of mammary or diaphragmatic tissue (intestinal handles), which are factors that interfere with the specificity of the exam. 6. Current Utilization of Myocardial Perfusion and Ventricular Function Studies with Radiopharmaceuticals as Part of the Medical Decision-Making Process MPS with the injection of radiopharmaceuticals associated with ET or the administration of coronary vasodilators is an established method for diagnosis and risk stratification of obstructive CAD, 91-100 with the aim of guiding more effective clinical management of patients as part of the medical decision-making process. 101,102 It currently integrates other non-invasive cardiovascular imaging techniques, such as Doppler echocardiography with color flow mapping, CS, coronary angio-CT, PET, and cardiac magnetic resonance (MR), to characterize risk and functional expression of atherosclerotic disease. 103 Accuracy of method was, until recently, based on invasive coronary cineangiography, considered the standard for this comparison. The following stand out as highly relevant aspects, considered of paramount importance to the modality: • Obtaining variables and parameters that are fundamental to incremental prognostic characterization of CAD, such as electrocardiographic response to exercise, functional capacity , chronotropic response, blood pressure, et al. Of all forms of stress associated to MPS, the exercise testing is, without a doubt, the one that adds the greatest amount of information. 104-106 • When analyzing perfusion images, the possibility of quantifying area of myocardial ischemia or myocardium at risk has advanced a great deal over the past decades, undoubtedly participating in risk stratification and medical decision making for stable CAD, where it provides assistance for the choice between maintaining clinical treatment and interventional treatment. 107 Even in the absence of randomized studies published to date, which might reaffirm this information (the Ischemia Study - report to the Addendum of this guideline), 108 the evidence which has currently been accumulated and made available documents better evolution in patients with severe ischemic burden who undergo myocardial revascularization. 109-112 • When analyzing ventricular function images, indirect observation of thickness and motility of the LV walls and comparison of resting and exercise ejection fractions greatly improve the method’s specificity for characterizing true ischemia and aggregate incremental prognostic value with the definition of markers of severity, such as transient ischemic dilatation (TID), representing ventricular dysfunction and / or subendocardic ischemia induced by applied stress. • The ability to infer coronary flow reserve under applied stress or stimulus with elevated accuracy, superior to other conventional methods, with the exception of PET, is the most important physiological parameter for characterization of ischemia and the medical decision- making process, currently available in clinical practice with direct invasive measures of FFR and instantaneous wave-free ratio (IFR). Software currently in development for calculating coronary reserve in association with SPECT methodology and other non-invasive methods will likely aggregate unquestionable value to appropriate clinical or interventional treatment choices, in the near future, encompassing not only obstructive atherosclerotic disease, but also physiopathological conditions, including microvascular disease and endothelial dysfunction in the scenario of ischemic heart disease. 85,113-115 The main applications with the best cost-effectiveness are shown in patients with intermediate pre-test probability of CAD, estimated based on the integration of clinical variables which have been established and documented in Brazilian and international guidelines, with their respective recommendations and levels of evidence (Tables 20 and 22 and Figure 11). Ideal diagnostic and prognostic capacities have for decades been considered with regard to severe coronary lesions. Nonetheless, exercise testing are indicated as the ideal and preferred association for myocardial scintigraphy, considering the physiological nature of the form of applied exercise and the established clinical value of the variables obtained during and after work. 116-120 Pharmacological tests performed in nuclear cardiology represent good alternatives for assessing patients with physical limitations or clinical limitations to undergoing efficient exercise testings. They include approximately 20% to 30% of all cases referred for scintigraphy and approximately 50% of elderly patients. 121 In these circumstances, the drugs utilized are dipyridamole, adenosine, 69,122,123 and regadenoson. 124 (Additional details described in Methodology.) Similarly, in practice, when comparing conventional algorithms used for established the probability of CAD 348